Checked that pansy just now. Found stem rot on the stems that dropped. Found this article
which was helpful.
No doubt the potting mix I used is not at the right PH either as I used the same potting mix as the vegetables.
5.0 and 5.5 is low.
May just as well discard the plant and the mix in the container.
Black Root Rot Of Pansy
"Adjust potting media to a pH between 5.0 and 5.5."